Toxocarosis in a patient with autism spectrum disorder presenting with severe hypereosinophilia and acute respiratory distress: a case report.

A boy with known autism spectrum disorder was transferred to our department due to a rapidly worsening respiratory situation. The patient's history revealed previous treatment with albendazole against a Toxocara infection 2 weeks prior in Poland. Blood analysis showed such severe eosinophilia and markedly elevated levels of IgE that, initially, a hematologic malignancy was suspected. However, diagnostic workup including autoimmune diagnostic, molecular genetic testing, fluorescence in situ hybridization (FISH), bone marrow aspiration, and parasitological testing led to the diagnosis of an insufficiently treated Toxocara infection. Treatment with albendazole and prednisone (six cycles for 4 weeks each) was administered. This treatment regime led to prompt improvement of symptoms and normalization of laboratory findings.

WormWatch: Park soil surveillance reveals extensive Toxocara contamination across the UK and Ireland.

BACKGROUND: Toxocarosis is a globally distributed zoonotic disease, but sources of infection are not well documented over large geographical scales. To determine levels of environmental contamination, soil from 142 parks and recreational areas across the UK and Ireland was assessed for the presence of Toxocara. METHODS: Toxocara ova (eggs) were isolated from soil samples by sieving and flotation and then enumerated. Individual eggs were isolated and imaged, and a subset was characterised by species-specific PCR and Sanger sequencing. RESULTS: Characteristic Toxocara-type eggs were found in 86.6% of parks, with an average of 2.1 eggs per 50 g of topsoil. Representative eggs were confirmed as Toxocara canis by Sanger sequencing, with many eggs containing developed larvae, hence being viable and potentially infective. Positive samples were more common, and egg density was higher, in parks with greater perceived levels of dog fouling. LIMITATIONS: Samples were collected at a single timepoint and with limited spatial mapping within parks. Further study is needed to discern spatiotemporal differences within parks and recreational areas. CONCLUSION: Toxocara is widespread in soil in public parks, indicating a need for further efforts to reduce egg shedding from pet dogs. Standardised methods and large-scale surveys are required to evaluate risk factors for egg presence and the impact of interventions.

Low exposure of urban dogs in metropolitan Sydney, Australia to Toxocara canis demonstrated by ELISA using T. canis excretory-secretory (E/S) larval antigens.

Canine roundworm, Toxocara canis, is considered ubiquitous but patent infections are rare in adult owned urban dogs. Hepato-pulmonary migration of T. canis is common in young dogs, but in adult dogs, the migration of T. canis is arrested in tissues and larvae are inhibited. During this somatic migration, T. canis release excretory-secretory (E/S) larval antigens against which the host mounts an immune response. Detection of anti-T. canis E/S immunoglobulins is considered a proxy for the presence of arrested somatic T. canis larvae. By screening several cohorts of dogs in New South Wales (NSW), Australia, we determined the seroprevalence of anti-T. canis E/S in urban owned dogs visiting a veterinary teaching hospital in Sydney to be 3.8 % (n = 53), which was significantly lower (two-proportion z-test, P < 0.05) than the seroprevalence in pet dogs in regional western NSW (22.2 %, n = 63), and rehomed greyhounds (53.6 %, n = 28). Using a logistic regression model, the risk of testing positive in regional pet dogs (odds ratio [OR] = 37.0) and rehomed greyhounds (OR = 81.0) was significantly higher than in urban dogs (P < 0.05). Although routine deworming of dogs eliminates patent infection, our data show a low number of urban dogs with anti-T. canis E/S antibodies, which implies that the majority of these dogs were not exposed to T. canis previously, do not possess inhibited T. canis larvae, and in the case of intact females, will not transmit it to their puppies.

Toxocara canis- and Toxocara cati-Induced Neurotoxocarosis Is Associated with Comprehensive Brain Transcriptomic Alterations.

Toxocara canis and Toxocara cati are globally occurring zoonotic roundworms of dogs and cats. Migration and persistence of Toxocara larvae in the central nervous system of paratenic hosts including humans may cause clinical signs of neurotoxocarosis (NT). As pathomechanisms of NT and host responses against Toxocara larvae are mostly unknown, whole-genome microarray transcription analysis was performed in cerebra and cerebella of experimentally infected C57Bl/6J mice as paratenic host model at days 14, 28, 70, 98, and 120 post-infection. Neuroinvasion of T. cati evoked 220 cerebral and 215 cerebellar differentially transcribed genes (DTGs), but no particular PANTHER (Protein ANalysis THrough Evolutionary Relationships) pathway was affected. In T. canis-infected mice, 1039 cerebral and 2073 cerebellar DTGs were identified. Statistically significant dysregulations occurred in various pathways, including cholesterol biosynthesis, apoptosis signaling, and the Slit/Robo mediated axon guidance as well as different pathways associated with the immune and defense response. Observed dysregulations of the cholesterol biosynthesis, as well as the Alzheimer disease-amyloid secretase pathway in conjunction with previous histopathological neurodegenerative findings, may promote the discussion of T. canis as a causative agent for dementia and/or Alzheimer's disease. Furthermore, results contribute to a deeper understanding of the largely unknown pathogenesis and host-parasite interactions during NT, and may provide the basis for prospective investigations evaluating pathogenic mechanisms or designing novel diagnostic and therapeutic approaches.

Antigenic Proteins from the Excretory-Secretory Products of Toxocara canis Larvae and Evaluation of Their Potential for Immunodiagnostics of Larval Toxocarosis.

BACKGROUND: Larval toxocarosis is a zoonosis caused by larvae of Toxocara canis and T. cati, a gastrointestinal nematode of canids and felids, respectively. Diagnosis is usually performed by ELISA IgG using Toxocara excretory-secretory products as an antigen. Due to laboriousness of isolation of the products and subsequent process of standardization of antigenic compounds, routine use of this method is limited and can produce inaccurate diagnostical results. The purpose of this study was to discover new specific antigenic proteins that could be used in routine serological methods of larval toxocarosis. MATERIALS AND METHODS: Toxocara excretory-secretory products were collected and separated by SDS-PAGE. Proteins from the gel were electro-transferred to a membrane and incubated with mouse sera. Antigenic proteins were analyzed using the liquid chromatography-tandem mass spectrometry approach. Selected proteins were prepared in recombinant form and tested with mice and human sera by ELISA and Western blot. RESULTS: A total of four recombinant protein antigens were prepared (rTc-TES-26, rTc-ASA, rTc-PDP, and rTc-ASP). They were analyzed by ELISA and Western blot using mice and human sera. For all sera, three of the four recombinant antigens correlated with Toxocara excretory-secretory products in ELISA analysis. By Western blot, the infection was confirmed in all experimentally infected mice and two out of seven human patients. CONCLUSION: Combination of the presented methods and analyses represents a possible method of effective identification of Toxocara protein antigens for the purpose of routine serodiagnosis.

Toxocara Seroprevalence and Risk Factor Analysis in Four Communities of the Wiwa, an Indigenous Tribe in Colombia.

The life of the indigenous Wiwa tribe in northeast Colombia is characterized by lacking access to clean drinking water and sanitary installations. Furthermore, free-roaming domestic animals and use of yucca and/or manioc as a primary food source favor the transmission of soil-transmitted helminths, e.g., Toxocara canis and Toxocara cati, the roundworms of dogs and cats. Infection may result in the clinical picture of toxocarosis, one of the most common zoonotic helminthoses worldwide. To estimate the Toxocara seroprevalence in four different villages of the Wiwa community, serum samples from 483 inhabitants were analyzed for anti-Toxocara-antibodies. Overall, 79.3% (383/483) of analyzed samples were seropositive. Statistically significant differences were observed between the four villages, as well as age groups (adults > adolescents > children), while sex had no effect. The high seropositivity rate demonstrates the risk of zoonotic roundworm infections and potential clinical disease in vulnerable indigenous inhabitants.

Toxocara canis and Toxocara cati Somatic and Excretory-Secretory Antigens Are Recognised by C-Type Lectin Receptors.

Toxocara canis and Toxocara cati, the worldwide occurring intestinal roundworms of canids and felids, represent an important public health threat due to various disease manifestations in humans. Host recognition of pathogens is mediated by pattern recognition receptors (PRRs). Myeloid C-type lectin receptors (CLRs) are PRRs and recognise carbohydrate structures of various pathogens. As Toxocara excretory-secretory products (TES) are predominantly composed of glycoconjugates, they represent suitable targets for CLRs. However, the range of host-derived CLRs recognising Toxocara spp. is still unknown. Using a CLR-hFc fusion protein library, T. canis and T. cati L3 somatic antigens (TSOM) were bound by a variety of CLRs in enzyme-linked immunosorbent assay (ELISA), while their TES products interacted with macrophage galactose-type lectin-1 (MGL-1). Two prominent candidate CLRs, MGL-1 and macrophage C-type lectin (MCL), were selected for further binding studies. Immunofluorescence microscopy revealed binding of MGL-1 to the oral aperture of L3. Immunoblot experiments identified distinct protein fractions representing potential ligands for MGL-1 and MCL. To evaluate how these interactions influence the host immune response, bone marrow-derived dendritic cell (BMDC) assays were performed, showing MCL-dependent T. cati-mediated cytokine production. In conclusion, MGL-1 and MCL are promising candidates for immune modulation during Toxocara infection, deserving further investigation in the future.

Seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran.

The World Health Organization has categorized toxocarosis as a neglected tropical disease despite its significant impact on high-risk groups such as children. This study aimed to investigate the seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran. A total of 386 children were enrolled in the study. All serum samples were tested for the presence of IgG antibodies against Toxocara spp. infection using an enzyme-linked immunosorbent assay. Moreover, relevant risk factors and clinical symptom data were obtained using questionnaires. Data analysis was performed using the SPSS software version 24. The overall seroprevalence of Toxocara spp. infection was found 2.85 % (11/386). However, Toxocara spp. infection was high for some risk factors, including eating soil (14.3 %), contacting cats (6.7 %), and consuming raw vegetables (3.7 %). However, there were no statistically significant differences regarding the risk factors and socio-demographic characteristics. Considering the clinical symptoms, Toxocara spp. infection was different in children with eosinophilia (20 %), ocular disorders (8.3 %), skin disorders (7.7 %), liver disorders (4.5 %), and stomach ache (4.2 %), although not statistically significant. The results revealed that the seroprevalence of Toxocara spp. infection was relatively low in children in northern Iran. It is suggested to conduct more studies in different parts of Iran to gain a deeper understanding of the toxocarosis seroprevalence and its status in high-risk groups such as children with asthma, hypereosinophilic syndrome, allergic skin disorders, and epilepsy.

A new ELISA and western blot technique based on recombinant TES antigen and/or larval antigen for the detection of toxocariasis in humans.

Serological antibody detection by enzyme-linked immunosorbent assay (ELISA)- and immunoblot-based methods constitutes the best indicator of human Toxocara infection. Nevertheless, the availability of serological tests, particularly western blots (WB), evaluated for sensitivity and specificity is limited. Therefore, an Anti-Toxocara-ELISA immunoglobulin g (IgG) prototype (Proto-ELISA) and an Anti-Toxocara-Westernblot (IgG) prototype (Proto-WB) were evaluated by testing 541 human sera pre-determined for Toxocara infection by an established in-house Anti-Toxocara-ELISA (IH-ELISA). To evaluate sensitivity and specificity of the newly developed ELISA and WB prototypes, results were compared to IH-ELISA and a commercial WB (Com-WB). Compared to the IH-ELISA, a sensitivity of 93.1% (229/246) and a specificity of 94.6% (279/295) of the Proto-ELISA with a Cohen's κ of 0.88 were obtained. The sensitivity of the Proto-WB was 76.7% (240/313) and specificity was 99.6% (227/228) with a Cohen's κ of 0.73 compared to those of Com-WB. A comparison to the IH-ELISA revealed 91.5% (225/246) sensitivity and 94.6% (279/295) specificity of the Proto-WB with a Cohen's κ of 0.86. Cross-reactivity was observed for some samples positive for Ascaris and Trichinella spp. in the Proto-ELISA, Proto-WB and Com-WB. Overall, the evaluated ELISA and WB prototypes showed high sensitivity and specificity, indicating high reliability of these newly developed tests.

Toxocariasis and the clinical spectrum.

Toxocara canis and T. cati are among the most widely distributed helminthic species in the world with a high zoonotic impact. Millions of people are infecteda and hundreds of thousands are suffering from toxocarosis, a disease encompassing four different entities: larva migrans visceralis (VLM) syndrome, ocular larva migrans (OLM) syndrome, covert toxocarosis (covT), common toxocarosis (comT) and neurotoxocarosis (NT). Toxocara infections in humans may remain clinically inapparent but may also induce severe diseases. This contribution gives a synoptic overview of the most important historical, clinical, diagnostic and therapeutical aspects of toxocarosis in humans.

Imaging of toxocariasis.

Several imaging modalities have now been employed to visualize the manifestations of larval Toxocara infection in hepatic, neurologic, ocular, renal, and other anatomical sites. This report reviews the usefulness and value of these individual imaging methods in diagnosis and follow-up of the different cases causing eosinophilic (granulomatous) infiltrations the liver, lungs, brain, heart, and eyes. Imaging provides a means of assisting in diagnosis and management in this infection where diagnosis by biopsy is often unlikely to capture an actual larva for the purpose of making a definitive diagnosis on the basis of larval morphology or DNA detection.

Toxocara-induced neural larva migrans (neurotoxocarosis) in rodent model hosts.

Neural larva migrans (NLM), or neurotoxocarosis, induced by Toxocara canis or Toxocara cati results from migrating and persisting larvae in the central nervous system of paratenic hosts, including humans. As the diagnosis of NLM in humans is not straightforward, most knowledge on the disease is derived from only a few published clinical cases. To improve our understanding of human NLM, studies on the pathogenesis and clinical symptoms in laboratory animal model systems are indispensable, and rodents have been accepted as the most appropriate model organisms for NLM. As research has mostly focused on neuroinvasive T. canis-larvae, information regarding the pathogenesis of T. cati-induced NLM remains scarce. This review summarises the current state of knowledge on neuroinvasion by both T. canis and T. cati in different rodent model hosts, the resulting behavioural changes, and histopathological alterations during the course of NLM as well as the potential molecular pathogenic mechanisms.

Toxocara canis and Toxocara cati in domestic dogs and cats in the United States, Mexico, Central America and the Caribbean: A review.

Toxocara prevalence ranges from 0 to >87% and 0 to >60% in dogs and cats, respectively, within the United States, Mexico, Central America and the Caribbean. Higher prevalence occurs in animals less than 1 year of age. Overall, prevalence is higher in cats compared to dogs. The lowest prevalence occurs in the US owned dog population. Specific populations in this industrialized nation, in animal shelters or resource-limited locations, have prevalences similar to those seen in populations from other regions reviewed here. Conversely, subpopulations in Central America and the Caribbean have very low prevalence. Apparent contributors to prevalence, excluding animal age and climate, are socio-economic factors, attitudes towards pet management and animal population density. The lack of data from some regions pose a challenge in assessing trends; however, with the exception of the US owned dog population, there is no strong indication of any decrease in prevalence from historical levels.

Toxocara vitulorum infection in a yak (Bos mutus grunniens) calf from Tyrol (Austria).

The domestic yak Bos mutus grunniens is an important livestock animal in parts of Asia, especially of the Himalayan region, where people rely on it for meat, wool, milk and labour. In its countries of origin, the yak is commonly infected with the ascarid Toxocara vitulorum. This parasite mainly infects cattle (Bos taurus) and domestic buffalo (Bubalus bubalus) and is most commonly found in sub-tropical regions, but has been occasionally reported in more temperate climates, including several Central European countries. Here we describe a fatal case of toxocarosis in a yak calf in Tyrol in May 2018, which is the first report of these parasites in yaks in Austria. A moribund calf had to be euthanized and gross pathology showed masses of cream-coloured, up to 25 cm long nematodes filling the whole of the small intestine, as well as parts of the colon. PCR of parts of the mitochondrial cytochrome c oxidase subunit I gene was performed and sequence analysis confirmed the helminths as Toxocara vitulorum.

Seroprevalence of Echinococcus spp. and Toxocara spp. in Invasive Non-native American Mink.

Invasive non-native species can become reservoirs of zoonotic pathogens and cause their spread during colonization, increasing the risk of zoonoses transmission to both wild hosts and humans. American mink (Neovison vison) are considered an important invasive mammal species responsible for carrying endoparasites. The aim of our study was to evaluate the role of feral American mink as a possible transmission vector of Echinococcus spp. and Toxocara spp. in wildlife. We analysed the frequency of American mink exposure to both parasites, the spatial distribution in Poland, and the variability over time on the basis of specific antibody presence using ELISA and Western blot. Alimentary tract analyses revealed that American mink do not serve as definitive hosts for these parasites. Altogether, 1100 American mink were examined. The average seropositivity for American mink was 14.2% for echinococcosis and 21.7% for toxocarosis; dual-seropositivity was detected in only 6.0%. Seroprevalence of both parasites differed between study sites and significantly increased over time in Toxocara spp. Thus, our study revealed that free-living American mink are exposed to parasites and likely to be involved in the maintenance of both Echinococcus spp. and Toxocara spp. in the wild as paratenic hosts.

Role of cats in human toxocarosis.

Toxocara cati, the feline ascarid, is ubiquitous in domestic cats globally and is increasingly recognised as an important zoonotic species. In the definitive host, infections with the adult ascarid usually do not present any clinical signs; if clinical signs do appear, it is usually in kittens infected with T. cati, especially by the transmammary route. Diseases may include cachexia, a pot-bellied appearance, respiratory disorders, diarrhoea, vomiting, among other signs, and these may present as early as 3 weeks of age. However, infections with Toxocara spp. larvae in paratenic hosts (including humans and many other animals), can result in serious complications from the migration of larvae. Historically, there has been an assumption that Toxocara canis was the most likely cause of Toxocara spp.-related disease; while it is probably true that T. canis is responsible for the majority of infections, it is important that those caused by T. cati are accurately identified so that the contribution of this parasite to human disease can be established and then handled appropriately. Overall, the detection of infections in cats and the control of parasite stages in the environment are essential to minimise the infection risk to other animals or humans.

Seroprevalence of Larval Toxocarosis in the Czech Republic.

BACKGROUND: Larval toxocarosis (LT), a zoonotic disease transmitted by dogs, cats, and other carnivores, is caused by roundworms of the genus Toxocara. Humans become infected by ingesting embryonated eggs of this parasite. In this study, we present data on the seroprevalence of LT in the Czech Republic collected by the National Reference Laboratory for Tissue Helminthoses in 2012-2016. METHODS: Using enzyme-linked immunosorbent assay, a total of 4428 adults and children with or without clinical symptoms were examined for the presence of IgG antibodies against Toxocara canis excretory-secretory antigens. RESULTS: Of all the persons examined, specific Toxocara antibodies were detected in 160 (3.6%) individuals. There were, however, significant differences between various regions, with seropositivity rates ranging from 1.4 to 7.5%. CONCLUSION: In comparison to studies from 1998 and 2004, our results suggest a decrease in overall Toxocara seroprevalence in the Czech population, whereby the rates are similar to or even lower than rates in some other Central European countries.

Histopathological Lesions Caused by Experimental Toxocara Canis and Toxascaris Leonina Infections in Farm Mink (Neovison Vison).

INTRODUCTION: Canine roundworm T. canis and T. leonina infections were investigated in experimentally infected farm mink (Neovison vison) to describe the pattern of pathological lesions in this paratenic host. MATERIAL AND METHODS: Material and MethodsInfections in mink developed following ingestion of embryonated eggs of either parasite or mice tissue infected with both parasite species. RESULTS: Comparative analysis of haematoxylin- and eosin-stained slides showed essential differences among the experimental groups. The lesions observed included eosinophil and mononuclear inflammatory infiltrates of the intestinal wall and local lymph nodes, inflammation and haemorrhages in liver tissues, and interstitial inflammation and mineralisation of the kidneys and lungs. Larvae migrating through the minks' bodies also caused particularly salient enlargement of lymphoid follicles in the spleen and inflammatory infiltrates of mononuclear cells in skeletal and heart muscles. CONCLUSIONS: It is assumed that histopathological lesions appeared as a local and general host response to invasive L3 T. canis and T. leonina larvae migrating through the tissues of infected farm mink. Interestingly, mink infected with embryonated eggs had more pronounced lesions than animals infected with tissue larvae. Detailed histopathological examinations of parenchymal organs and striated muscles revealed lesions resembling those observed in other paratenic host species due to toxocarosis.

Neuroinvasion of Toxocara canis- and T. cati-larvae mediates dynamic changes in brain cytokine and chemokine profile.

BACKGROUND: Neurotoxocarosis (NT) is induced by larvae of the dog or cat roundworm (Toxocara canis or T. cati) migrating and persisting in the central nervous system of paratenic hosts, including humans, and may be accompanied by severe neurological symptoms. Host- or parasite-induced immunoregulatory processes contribute to the pathogenesis, but detailed data on pathogenic mechanisms and involvement of signalling molecules during cerebral Toxocara species infections are scarce. METHODS: To elucidate alterations in immunomodulatory mediator pattern, comprehensive multiplex bead array assays profiling comprising 23 different cytokines and chemokines were performed during the course of T. canis- and T. cati-induced NT. To this end, cerebra and cerebella of experimentally infected C57Bl/6 J mice serving as paratenic host models were analysed at six different time points (days 7, 14, 28, 42, 70 and 98) post infectionem (pi). RESULTS: Brain-body mass ratios of T. canis and T. cati-infected mice were significantly lower than those of the uninfected control group at day 14 pi, and also at day 28 pi for T. canis-infected mice. Both infection groups showed a continuous decrease of pro-inflammatory cytokine concentrations, including TNF-α, IFN-γ, GM-CSF and IL-6, in the cerebrum over the course of infection. Additionally, T. canis but not T. cati-induced neurotoxocarosis was characterised by significantly elevated levels of anti-inflammatory IL-4 and IL-5 in the cerebrum in the acute and subacute phase of the disease. The higher neuroaffinity of T. canis led to a prominent increase of eotaxin and MIP-1α in both the cerebrum and cerebellum, while in T. cati-infected mice, these chemokines were significantly elevated only in the cerebellum. CONCLUSIONS: The direct comparison of T. canis- and T. cati-induced NT provides valuable insights into key regulatory mechanisms of Toxocara species in paratenic hosts. The cerebral cyto-/chemokine milieu is shifted to a predominantly anti-inflammatory immune response during NT, possibly enabling both survival of the parasite and the neuroinfected paratenic host. Alteration of eotaxin and MIP-1α concentrations are congruent with the higher neuroaffinity of T. canis and species-specific tropism of T. canis to the cerebrum and T. cati to the cerebellum.

[Helminths detection with video capsule endoscopy].

The article describes clinical observations of helminthiasis detection in 18 of 208 patients during video capsule endoscopy (VCE). Indications for the appointment of VCE were complex clinical situations associated with the search for inflammatory diseases of the small intestine and sources of small intestine bleeding. Because of the high cost of VCE the diagnosis of parasitic diseases should be based on laboratory techniques in clinical practice. Only in case of anemia of unknown etiology VCE demonstrates high efficiency.